Bathroom tiles lifted

[jobirdster]

Hi;

I am a homeowner who recently had an extension built with a ensuite, we bought Pro warm electric underfloor heating kit and a 600 x 600 tile for the floor

We had them installed pre Christmas and this last week the middle section of the tiles have all lifted / peaked up and cracked. 4 tiles right in the middle of the bathroom are affected but all the other tiles now sound hollow too when we tap them.

The method for install was a thermal board, electric matt, screed and primer which came with the pro warm mat.
The tiler insists he has used a good quality adhesive Ultra Flexible
We did not turn the electric mat on for at least 6 weeks after install.
When I look at the back of the lifted tiles they are clean, no adhesive on them... adhesive seems to have stayed on the screed.

My questions.
Do we need expansion gaps on this size of floor with electric underfloor heating ? size is no larger that 3m x 3m tiles are 600mm x 600mm porcelain matt and are sold as suitable for underfloor

I have had another tiler out and he states that its either substandard adhesive, not being primed properly or no back buttering of the tiles.

The tiler who fitted them said he never back butters, the primer he used was supplied from the underfloor heating kit and the adhesive he used was Ultra Flexible.

Can anyone shed any light on what could have happened please ?

I need to find a solution/ idea of whats gone wrong so I can get the tiler to correct it.

 

[J Sid]

Expansion joint all round perimeter.
Not back buttering tile is the most likely cause imho
Pics are good if you can

 

[Dumbo]

As above i agree with julian

 

[jobirdster]

Hi Julian;

Thank you for your comments.

Here are some pics. Tiler who did the job told me no expansion gaps is needed on such a small area and he only back butters to fill up on an uneven floor gap, but not as a standard way to install.

Pics are attached to show you

 

[J Sid]

No explanation joint around perimeter looks like the cause
Should have back buttered but could still have popped without explanation joint.
Original tile should redo it

 

[eddcottee]

Julian, if there is no expansion gap around the perimeter then I get that is the likely cause, however when re-installing, along with the necessary expansion gap, would a decoupling membrane not be a good idea given what has happened to that floor already? Or do you not feel it necessary? Large format tiles with UFH says decoupling membrane to me, but I'm still learning the trade. Cheers. Edd

 

[Anthony]

did You turn the heating on gradually?
[automerge]1582145322[/automerge]
As this looks to me from the way they have cracked and lifted like rapid heat ingress

 

[Dhtiling]

Pretty poor contact and trowel technique. Expansion joints at all edges are required. Back buttering helps with bonding, but not required. Heated floors were done properly for years before membranes came out, just looks to be a bad install. Shouldn't be able to see ridges from trowel.

 

[eddcottee]

Pretty poor contact and trowel technique. Expansion joints at all edges are required. Back buttering helps with bonding, but not required. Heated floors were done properly for years before membranes came out, just looks to be a bad install. Shouldn't be able to see ridges from trowel.

I did wonder about those swirls from the trowel. I was taught you have them all running in the same direction, then when you set the tile in, move it a few mm each way and back into place which collapses the ridges and gives you a good bed. Was also taught to back butter and have seen what a difference this makes whenever lifting to occasionally check a tile. Usually immediately after setting a tile down, if I have to lift it for some reason, it's really very hard work to pull the tile back up. I can't imagine those tiles would have taken any effort to lift back up.

 

[J Sid]

Julian, if there is no expansion gap around the perimeter then I get that is the likely cause, however when re-installing, along with the necessary expansion gap, would a decoupling membrane not be a good idea given what has happened to that floor already? Or do you not feel it necessary? Large format tiles with UFH says decoupling membrane to me, but I'm still learning the trade. Cheers. Edd

No membrane is needed with those tiles, thin porcelain and stone, yes.
Bad fixing technique, a membrane would not have helped in this situation Edd

 

[eddcottee]

No membrane is needed with those tiles, thin porcelain and stone, yes.
Bad fixing technique, a membrane would not have helped in this situation Edd

Thanks Julian

 

[jobirdster]

Thanks to you all. You have mentioned exactly what the tiler who came to look at it said.

Just so I know, for an expansion gap what does it consist of ? Is the gap filled with silicone or with tile grout ?

 

[widler]

Is there skirting on, is it tiled up to wall tiles , a couple mm gap then silicone or gap than no silicone then skirts
[automerge]1582196135[/automerge]
Just seen its tiled up to tile, so silicone .
I know every customer says it gradually turned the heating on, but hand in hete , did u wack it in full pelt straight away ?
[automerge]1582196175[/automerge]
‘Hand on heart’

 

[J Sid]

Thanks to you all. You have mentioned exactly what the tiler who came to look at it said.

Just so I know, for an expansion gap what does it consist of ? Is the gap filled with silicone or with tile grout ?

5mm gap round room, clean of adhesive and grout then silicon this gap

 

[jobirdster]

Is there skirting on, is it tiled up to wall tiles , a couple mm gap then silicone or gap than no silicone then skirts
[automerge]1582196135[/automerge]
Just seen its tiled up to tile, so silicone .
I know every customer says it gradually turned the heating on, but hand in hete , did u wack it in full pelt straight away ?
[automerge]1582196175[/automerge]
‘Hand on heart’

There is wall tiles on most of the walls, just two areas with a small tile skirt. Rest butt up to wall tiles.

We didn't have the electrics connected for at least 6 weeks, (might have been even longer) after the tiles were laid. We waited ages for the sparky to come back.

Hubby turned on and is sure he put it on 16 degrees at start and then up to 20 .

 

[Smiler5714]

Defo expansion gap needed but also with any underfloor heating you need a solid bed of adhesive. One reason for needing a solid bed is for thermal transfer of heat up from the mat and through into the tile. Air is a very poor conductor of heat and so if you have air trapped between trowel ridges you have a very uneconomical system. Secondly, if the air pockets are quite large you can also have a problem where the heated air expands and again, it could possibly cause lifting of the tiles, especially if they weren't very well bedded to start with.

When solid bedding it's always better to butter the back of the tile.

 

[al strachan]

ignore

 

[Etherglide]

The trowel marks look like !0mm at the most. I suspect not back buttered. Oh, and the heating was turned on too quick. Dismiss an expansion joint at the walls. Most of us, if were being honest, don't tile tight to the wall anyway.

 

[jobirdster]

The trowel marks look like !0mm at the most. I suspect not back buttered. Oh, and the heating was turned on too quick. Dismiss an expansion joint at the walls. Most of us, if were being honest, don't tile tight to the wall anyway.

It took us over 6weeks to have the electrics for the UFH connected. We were advised 2 weeks was enough but we didn't have a sparky on site for ages.

 

[J Sid]

It took us over 6weeks to have the electrics for the UFH connected. We were advised 2 weeks was enough but we didn't have a sparky on site for ages.

Its the turning on and how the heat is ramped up slowly over the next week which is very important after the tiles and adhesive has set.
Turning the ufh on and taking it high straight away could give thermal shock leading to floor failure, looking like your floor looks now

 

[jobirdster]

Its the turning on and how the heat is ramped up slowly over the next week which is very important after the tiles and adhesive has set.
Turning the ufh on and taking it high straight away could give thermal shock leading to floor failure, looking like your floor looks now

Thank you to all who commented, we had someone independent to come out to assess on Friday and he has concluded that its the prep. Specifically no primer being used, which the tiler has admitted to only using the small bottle of primer that came with the UFH kit.

So now to get it corrected !

 

[J Sid]

From the pic's you posted I can't see it as a primer issue.
The adhesive has stuck to the floor and not stuck to the tile at all. Bad fixing method/no explanation.
Hope you get it sorted and maybe worth asking the next Tiler for commissioning process for ufh

 

[Anthony]

From those pictures posted it’s definitely the ufh getting to hot to quick! When tiles are insufficiently stuck they won’t crack and lift like that they’ll de bond and sit on the surface grout will crack giving that away. When stuck properly the adhesive will shrink and hold under tension (factor in curing time) then when heat is applied to quickly the properties of the adhesive can’t keep up causing lift and cracking. And debonding as tension is lost to quick. Certainly nothing to do with primer !

 

[eddcottee]

Where was this independent person from? I cant understand how primer is the issue, as the adhesive seems to have taken quite nicely to the floor. Albeit the adhesive has been poorly laid. If the issue was primer, the adhesive wouldn't have stuck to the substrate surely?